Knowledge Base

Glossary

Aeromagnetic

Measurments of the Earth's local magnetic field made from an airborne platform - usually a plane.

Antiform

A fold structure in a rock unit or package of rocks where the fold apex points upwards - forming an arch structure in profile.

Artisanal

Said of mine workings created by individual human effort - usually dug by hand or with simple tools - as opposed to industrial scale mining undertaken with mechanical support infrastructure.

ASEG

An acronym for the Australian Society of Exploration Geophysicists.

Basal

At the base of something (often used in relation to a rock unit or sequence of units).

Bond Work Index

A measure of the power needed to crush a tonne of material.

Boudinage

The separation of a competent rock mass into discrete fragments due to ductile extension of an encompassing, less competent rock mass - producing a linear array of elongate bodies aligned in the direction of extension.

Breccia

A rock composed dominantly of angular fragments derived from the mechanical breakdown of a pre-existing rock mass.

Cleavage

A planar weakness within a body of rock that presents a preferential fracture plane during the mechanical breakdown of the rock mass.

Conglomerate

A sedimentary rock where the dominant constituent fragments are pebble-sized or larger, and display rounding consistent with having been transported some distance form their original source.

Conjugate

Referring to a pair of faults, shear zones, or other structural features with opposite dips or vergences.

Contact

The boundary between two discrete rock masses.

Crust

1. A hardened layer, coating, or deposit on the surface of something soft.
2. The outermost chemically and mineralogically distinct layer of the Earth (or other Terrestrial planet).

Cryptic

A descriptor applied to a process or phenomenon whose effects cannot be observed directly, but are nevertheless reliably inferred or required by indirect evidence.

Cumulate

An igneous rock formed by the gravitational settling of early-formed crystals within a body of magma,

DCF analysis

A method of financial valuation based on projections of future income.

Detrital

Derived from erosion and transport of another rock unit.

Dextral

Moving to the right

Diachronous

Spread over a range of times, or occurring at different times.

Dip

A component of planar geometry, describing the inclination of a plane measured perpendicular to its direction of strike.

Dip-slip fault

A fault on which the dominant movement is parallel to the dip of the fault surface.

Disseminated mineralisation

Mineralisation dispersed throughout a host rock, rather than focused in veins or other coherent bodies.

Ductile

Descriptive of deformation achieved by recrystallisation or reorganisation of material framework without brittle fracturing occurring.

En-echelon

An arrangement of parallel line or plane segments where each is displaced laterally from its neighbours in a consistent sense.

Exhalative

Produced by the expulsion of fluids - usually at elevated temperatures - from a body of rock.

Fault

A fracture through a rock mass accommodating movement.

Footprints

The area covered by something

Global

Relating to the whole world; worldwide.

Gneiss

A rock metamorphosed to such a degree that reordering and recrystallisation of its constituent materials has produced segregation into mineralogically distinct layers.

Granite

A coarse grained igneous rock with a high silica content, typically crystallised a significant distance (kilometres) below the surface.

Granitoid

A loose term for a 'granite-like' lithology - typically applied to coarse-grained silica-rich (and thus relatively pale) igneous rocks whose precise lithology has not yet been identified by chemical or other means.

Greenstone

1. A general term for a dark green, low to medium grade metamorphosed basic igneous rock - particularly when describing geology at a regional scale.
2. A loose term in general use for a group of metamorphic and igneous rocks including amphibolite, gabbro, some schists, epidorite, serpentine, and jade.

Hydrothermal

Related to the production or passage of water or other fluids through a rock mass at elevated temperature.

Hyperspectral

Pertaining to data gained by analysing an object or sample with electromagnetic radiation at a multitude of finely resolved wavelengths potentially including, but not limited to, ultravioliet radiation, visible light, infrared radiation, and radio waves.

IMF

An acronym for the International Monetary Fund - an international financial organisation working to foster global monetary cooperation, secure financial stability, and facilitate international trade.

Inclusion

A discrete fluid or crystalline mass enveloped within a larger crystalline body.

Intrusion

1. (verb) The act of emplacing a liquid magma within a pre-existing rock mass.
2. (noun) A body of crystalline rock produced by the cooling and solidification of a magma.

JORC Code

A professional code of practice laying out the minimum standards for Public Reporting of minerals Exploration Results, Mineral Resources and Ore Reserves.

Juxtaposed

Next to each other.

Kinematic

Describing phenomena measured in relation to the relative motion of an object.

Komatiite

A magnesium-rich form of ultramafic rock. Formed by partial melting of the deep mantle under unusually hot (for the present Earth) temperatures.

Lithostratigraphy

Ordering and correlation of rock units on the basis of their fundamental geological character, rather than alternative distinguishing characteristics (such as absolute or relative age, geochemistry, or isotopic properties).

Mafic

Describing a crystalline (most commonly igneous, but also used for metamorphic) rock that is low in silica content and consequently dark and relatively dense.

Magma

A melt (most commonly silicate based - more rarely carbonate), commonly containing suspended crystals and/or dissolved volatile components, produced by the partial or total melting of a pre-existing body or rock.

Magnetotellurics

A geophysical method for inferring the Earth's subsurface electrical conductivity from measurements of natural variations in the magnetic and electric fields measured at the Earth's surface.

Metamict

An amorphous state attained through the disruption of a crystal structure by radiation damage.

Metasediment

A metamorphic rock for which the original (or parent) material can be texturally or chemically identified as having been a sedimentary rock.

Mineralisation

1. (verb) The process of concentrating specific (usually economically valuable) minerals within a discrete volume of rock.
2. (noun) A concentration of economically valuable minerals within a body of rock.

Mineralogical

Relating to the minerals making up a particular sample.

Mining

The process or industry of obtaining coal or other minerals from a mine.

Monomict

Composed of fragments of a single rock type.

Morphological

Description of an object on the basis of its form.

MRIWA

An acronym for the Minerals Research Institute of Western Australia.

NIR

An acronym for Near Infrared - referring to the near-infrared region of the electromagnetic spectrum, with wavelengths in the region of 800-2500 nm.

Normal fault

A dipping fault structure on which the body of rock above the fault (hanging wall) moves downwards in relation to the body of rock below the fault (foot wall), producing net extension of the rock mass.

OECD

An acronym for the Organisation for Economic Co-operation and Development - a leading international economic forum of countries committed to democracy and the market economy.

Orogenic

Deriving from, or related to, the process of orogeny - deformation of the Earth by tectonic processes, particularly leading to the development and growth of mountains.

Orogeny

Deformation of the Earth by tectonic processes, particularly leading to the development and growth of mountains.

Outcrop

An exposure of solid rock at the Earth's surface.

Pegmatite

A very coarse grained igneous rock composed of interlocking crystals several cm or more in diameter. Most commonly observed in rocks of granitic composition.

PGE

An acronym for Platinum Group Elements - platinum, rhodium, ruthenium, and related metals.

Pluton

A substantial body of formerly liquid rock (magma) cooled and crystalised below the surface of the Earth.

Polymict

Composed of fragments of multiple different rock types.

Porphyry

(1) An igneous rock, typically of a silica-rich composition, with large crystals in a finer-grained matrix.
(2) A mineral deposit whose genesis is associated with such rocks.

Raman spectroscopy

An analytical technique for constraining material composition through the scattering of monochromatic light, usually from a laser source, at a number of wavelengths.

Regolith

Reverse fault

A dipping fault structure on which the body of rock above the fault (hanging wall) moves upwards in relation to the body of rock below the fault (foot wall), producing net shortening of the rock mass in the horizontal plane.Synonymous with 'thrust fault'.

Rheology

Study of the flow and deformation of materials.

Scintillometer

An analytical device for measuring the rate of radioactive decay in the immediate environment.

Shear

Ductile deformation in which the angular relationship between material lines in a body is changed - producing a rotational strain.

Shear zone

A discrete domain of rock across which shear is accommodated.

SHRIMP

A common acronym used for the Sensitive High Resolution Ion Microprobe - an analytical instrument typically used for the targeted dating of individual crystals or sub-crystal domains, but also applied to other isotopic analyses.

Silicate

A crystalline material dominated by the presence of silica.

Sinistral

Moving to the left

Sinusoidal

Describing a surface exhibiting a repeating series of peaks and troughs - like a mathematical sine wave function.

Spatial

Relating to the geographic relationship of objects or points to one another.

Spectroscopy

The study of the interaction between matter and radiated energy - in particular, the absorption and reflection of specific wavelengths of electromagnetic radiation.

Stereonet

A graphical device for plotting and interpreting 3-dimensional structural information.

Strike

A component of planar geometry, describing the orientation of a horizontal line on a dipping plane.

Strike-slip fault

A fault on which the dominant movement is parallel to the strike of the fault surface.

Synform

A fold in a rock unit or sequence of rocks where the fold apex points downwards.

Temporal

Relating to time.

Terrane

A fault-bounded region with a geological character and/or history differing significantly from neighbouring regions.

Tholeitic

A descriptive prefix applied to igneous rocks, denoting their derivation from progressive crystallisation of a mafic magma with high iron and/or magnesium content.

Thrust fault

A dipping fault structure on which the body of rock above the fault (hanging wall) moves upwards in relation to the body of rock below the fault (foot wall), producing net shortening of the rock mass in the horizontal plane.Synonymous with 'reverse fault'.

Tomography

Construction of an image of the subsurface through combined interpretation of multiple penetrating waves.

Ultramafic

Describing a crystalline (most commonly igneous, but also used for metamorphic) rock that is extremely low in silica content and consequently very dark and dense.

UNCOVER

A national research vision for exploration geoscience in Australia, expressing the shared industrial, academic, and government mission to develop new paradigms to support greenfields mineral exploration below cover rocks.

Uniformitarianism

A geological philosophy contending that Earth history can be understood entirely on the basis of the same processes and phenomena that we can see in operation around the world today.

Vein

A sheet-like or tabular mineralised body - usually discordant to its host rock - formed by the partial or complete infilling of a fracture within a pre-existing rock mass.

Volcanic province

A regional scale area affected by a common process and/or period of volcanic activity.

Volcanogenic

Produced by or formed within a volcanic system.

XRF

An acronym for X-ray Fluorescence analysis - a method of instrumental analysis of material composition utilising the variable fluorescence of different minerals under X-rays.